Cold-forming process and apparatus

ABSTRACT

This invention relates to sheet metal buildings of relatively large size and more particularly but not exclusively to processes and apparatus for cold-forming elongate building elements of such buildings and methods of building construction. The invention provides in one aspect cold-forming dies  30,  mounted on intermediate transverse members  21  of a frame  1,  comprising a set of coextensive generally in register dies between which the strip is received. The set comprises a male die  22  having a concave leading edge  24  and a female die  23  having a convex leading edge  18.  The male die  22  and female die  23  are driven towards one another to plastically deform the strip  6  into a channel section. The concave leading edge  24  is provided with a coextensive protrusion  26  and the convex leading edge is provided with a coextensive recess  27.  At the same time that the dies  22, 23  mate to plastically deform the strip  6  into a channel section the protrusion  26  and recess  27  of the respective dies  22, 23  mate to form a transverse rib  28  in the strip  6.

This application is a 371 of PCT/AU98/00517, filed Jul. 3, 1998.

TECHNICAL FIELD

This invention relates to sheet metal buildings of relatively large sizeand more particularly but not exclusively to processes and apparatus forcold-forming elongate building elements of such buildings and methods ofbuilding construction.

BACKGROUND ART

The invention is particularly described with reference to longitudinallyarcuate building elements. Typically building elements of this kind havebeen used to construct farm buildings, garages and the like of upwardlyconvexed arched structure comprising a plurality of prefabricatedlongitudinally arcuate elements that extend continuously from one sidefoundation of the building to the other arranged side by side with theirabutting edges secured together thereby forming a stand alone buildingdevoid of bracing, trusses or other structural reinforcements.

Traditionally the elements have been formed in two or more passesthrough roll forming apparatus or have required very long roll forminglines. Conventional processes and apparatus generally produce relativelyshort span elements which for long span buildings have been joined endto end with overlapping edge margins. Consequently, in constructing longspan buildings, typically the short span elements are either joined endto end on the ground prior to being hoisted into position alongsidepreviously erected elements and subsequently secured thereto edge toedge or are hoisted into their desired position individually for joiningend to end and side to side with previously erected elements.

Both methods of construction are labour intensive and expensive.

Previously proposed buildings of this kind have not proven popular fromeither a commercial or manufacturing aspect. This appears dueprincipally to high costs involved in formation and transportation ofthin sheet metal elements of this kind and to handling difficulties andother constructional problems associated with such elements. Hence it ispreferred that the formation of the building elements takes place at thesite of the building to be erected. However, it has been found thatconventional apparatus requires very long forming lines with amultiplicity of sets of forming rollers and as such have been somewhatimpractical.

To address these problems the present inventor has previously proposedin Australian Patent application no. 48883/90 a method of erecting suchbuildings and apparatus for forming building elements of the above kind.Although the proposal goes a long way towards providing an effective andefficient solution to these problems it has been found that the proposedapparatus does not have sufficient operational flexibility to providefor building spans exceeding 20 meters. Additionally said apparatus isnot sufficiently operationally flexible to provide adjustment of radiusof curvature of the elements during operation and/or withoutconsiderable rearrangement and realignment of equipment and time loss.

An object of the present invention is to provide a process and apparatuswhich addresses one or more problems and deficiencies identified aboveor later in the specification.

SUMMARY OF THE INVENTION

The present invention provides apparatus for forming an elongatelongitudinally arcuate building element of channel cross-section havingtransverse ribs from sheet metal comprising a set of coextensivegenerally in register dies through which a sheet of metal can bereceived, said set comprising a male die and a female die whichcooperate to form transverse ribs in the sheet wherein further one ofsaid male die and female die is provided with a concave leading edge andthe other die is provided with a convex leading edge thereby the diescooperate to plastically deform the sheet into a channel section.

It is preferred that the male die is provided with an upright protrusionprojecting from its leading edge and extends along at least part of itslength.

It is also preferred that the female die is provided with a coextensiverecess extending along at least part of its length.

More preferably, both the protrusion and the recess extend a majorportion of their respective edges.

It is preferred that the leading edges remain in register duringoperation of the apparatus.

Preferably the dies are provided with orbital motions which cooperate tobring the dies into engagement with the sheet, draw the sheet along atransit path therebetween while cold-forming the sheet and thendisengage the sheet with each sweep about their orbits.

It is preferred that the dies are provided with means to adjust theradius of curvature of either or both the respective concave leadingedge or the convex leading edge.

Adjustment of the radius of curvature of a leading edge may, forexample, be effected by means of providing a female die formed of aplurality of segments held side to side having a gap provided between atleast a portion of each of the segments, the width of the gap beingadjustable so as to effect adjustment of the radius of curvature of theleading edge.

In one embodiment the die is formed of two substantially identical halfsegments.

Preferably the half segments are hinged to one another towards theirleading end.

It is also preferred that the said set of dies are mounted on crankmechanisms to provide the dies with said cooperating orbital motions. Inembodiments of this kind the dies may engage respective opposite sidesof the sheet as it travels along a transit path through the apparatus,plastically deform the engaged portions of the sheet to form transverseribs and advance with the sheet as deformation occurs, then release thesheet as it advances further along its transit path. Simultaneously thedies plastically deform the sheet into channel section by virtue oftheir respective concave and convex leading edges. This step may berepeated for each rib.

It has been found that the radius of longitudinal curvature of theelement is closely related to the number of ribs per unit length of theelement and as such is a function of both the speed of orbital motion ofthe dies and the speed of the sheet advancing along its transit path. Ithas also been found that the depth of the ribs also influence saidcurvature. The present invention facilitates rapid presetting of theradius of longitudinal curvature of the element by simple presetting oforbital motion speed and die intrusion length, without the need to altersheet advancement speed and enables adjustment of said radius duringoperation of the apparatus by simple adjustment of the speed of orbitalmotion of the dies.

It is preferred also that guide means is provided in advance of the diesto receive the strip from a coil in a substantially flat configurationand pass the strip to a arcuate nip formed by the leading edges of thedies in a shape in cross-section corresponding generally to the shape incross-section of the arcuate nip without plastically deforming the stripinto said shape.

It is also preferred that drive means in the form of, for example, driverollers is provided in advance of the guide means to drive the sheet inthe form of strip from the coil to the dies through the guide means.

It is preferred that the apparatus further comprises edge flange formingmeans to operate on each longitudinal edge of the sheet.

More preferably the edge flange forming means comprise at least twopairs of cooperating edge forming rollers with each pair of rollersoperating on a respective longitudinal edge to form flanged edges.

The flanged edges of each sheet may be formed as respective male andfemale formations so that two elements disposed side by side withoverlapped flanged edges enable the male formation of one element tonestle in the female formation of the other element.

It is preferred that the sheets are provided from a coil of strip andthat the apparatus further comprises shears to cut said strip intosheets of predetermined length. The shears may be disposed in advance ofthe forming dies so that discrete sheets pass through the forming diesor more preferably downstream thereof so that the cold-formed strip iscut into cold-formed elements.

It is preferred that the transverse ribs comprise corrugations. Thecorrugations may, for example be substantially sinusoidal incross-section.

The crank mechanism may, for example, comprise four crankshaftsrotatably supporting each die. Four bearing housings may be mounted oneach die with two housings disposed on either edge margin of each die,one housing of said two housings being mounted towards the leading endof the die and the other towards the trailing end.

Each set of four crankshafts may be rotatably supported by eight bearinghousings mounted on the frame, two housings for each crankshaft, and maybe driven by an electric motor through a drive chain. The drive chainmay, for example, comprise a chain and sprocket arrangement providing agear reduction.

Four drive sprockets may drive the crankshafts of the male die and mayrotate them in a clockwise direction and by running the back of thechains against the drive sprockets of the female die these sprockets maybe driven counterclockwise.

It is preferred that the dies are driven by means of a chain andsprocket arrangement whereby synchronisation of movement of the dies isfacilitated.

The dies may be so geared to one another that they move towards oneanother to engage the strip received between them, advance with thestrip along a transit path therebetween then disengage from the strip asthey move further along their respective orbital path created by themovement of the crankshafts.

The offset of each crankshaft may, for example, provide each die witheccentric displacement with respect to the frame thereby providing thedies with both rotational and reciprocating action which permitscontinuity of strip feed.

The dies may thus be provided with both vertical and horizontal movement(as illustrated in FIGS. 10 to 13) as their cooperating respectiveconcave and convex edges sweep said orbital path (in side view) withoutdeparting from their orientation towards one another. That is to say,the concave edge and the convex edge lie in register during operation.

The present invention also provides a process of forming an elongatelongitudinally arcuate building element of channel cross-section havingtransverse ribs from sheet metal comprising the steps of; directingsheet metal to a nip of a set of dies, providing a set of coextensivegenerally in register dies having a nip through which a sheet of metalcan be received, said set comprising a male die and a female die whichcooperate to form transverse ribs in the sheet wherein further one ofsaid male die and female die is provided with a concave leading edge andthe other die is provided with a convex leading edge thereby the diescooperate to plastically deform the sheet into a channel section anddriving said dies to bring them together to form said transverse ribs inthe sheet and to plastically deform the sheet into channel section priorto disengaging the cold-formed element.

It is preferred that the leading edges are held in register duringoperation of the apparatus.

Preferably the dies are provided with orbital motions which cooperate tobring the dies into engagement with the sheet, draw the sheet along atransit path therebetween while cold-forming the sheet and thendisengage the sheet with each sweep about their orbits.

It is also preferred that the said set of dies are mounted on crankmechanisms to provide the dies with said cooperating orbital motions.

It is preferred that the process further comprises the step of edgeflange forming each longitudinal edge of the sheet.

It is preferred that the process includes the step of providing metalsheets from a coil of strip and then cutting said strip into sheets ofpredetermined length.

The invention extends to a die for use in cold-forming apparatus saiddie having a leading end and a trailing end characterised in that theleading end is provided with an arcuate leading edge to cooperate with aleading edge of another die to plastically deform sheet metal into achannel section, the die being formed of a plurality of segments heldside to side and a gap being provided between adjacent corners of theleading end of the segments, wherein the width of the gap is adjustableto effect adjustment of the radius of curvature of the arcuate leadingedge.

It is also preferred that the die is formed of substantially identicalhalf segments and that half segments are hinged to one another to effectsaid adjustment of the radius of curvature of the arcuate leading edge.

The present invention enables a sheet of metal to be formed into anelongate longitudinally arcuate building element of channelcross-section having transverse ribs in one pass through a single set offorming dies and obviates the need for a long transit path typical ofconventional apparatus.

The present invention also provides cold-forming apparatus forcold-forming strip comprising cold-forming means to plastically deformthe strip and support means to support the cold-forming means in apredetermined orientation characterised in that the support meansenables the cold-forming means to be rotated about an axis substantiallyparallel to a travel path of the strip through the cold-forming meansand held at one or more discrete orientations so that the formed stripissues from the apparatus at a desired orientation.

The present invention also provides cold-forming apparatus forcold-forming strip comprising a frame supporting cold-forming means toplastically deform the strip and strip guide means in advance of thecold-forming means, wherein the frame is provided with frame supportmeans to support the frame in a predetermined orientation and whereinthe frame support means enables the frame to be rotated about an axissubstantially parallel to a travel path of the strip through thecold-forming means and held at one or more discrete orientations so thatthe formed strip issues from the apparatus at a desired orientation.

It is preferred that the guide means passes the strip to thecold-forming means and present the strip to the cold-forming means in ashape in transverse cross-section substantially corresponding to that tobe formed by the cold-forming means.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more fully explained one particularembodiment will be described in detail with reference to theaccompanying drawings in which:

FIG. 1 is a schematic side elevation view of cold-forming apparatus inaccordance with a preferred embodiment of one aspect of the invention.

FIG. 2 is a schematic side view of important components of thecold-forming apparatus of FIG. 1

FIG. 3 is a schematic view of components illustrated in FIG. 2 takenalong the lines 3—3.

FIG. 4 is a schematic view of components illustrated in FIG. 2 takenalong the lines 4—4.

FIG. 5 is a schematic view of components illustrated in FIG. 2 takenalong the lines 5—5.

FIG. 6 is a schematic view of the apparatus illustrated in FIG. 2 takenalong the lines 6—6.

FIG. 7 is an enlarged scrap section of important components illustratedand enclosed by the arrow 7 in FIG. 6.

FIG. 8 is a cross-sectional view of the components illustrated in FIG. 7taken along the line 8—8.

FIG. 9 is a cross-sectional view of the components illustrated in FIG. 7taken along the line 9—9.

FIG. 10 is a schematic cross-sectional view of the strip and the diesillustrating their relative positions at the end of the cold-formingstrokes of the respective dies with a scrap illustration of the orbitalmotion of the female die and the relative position of the leading edgeof the female die at this stage of the cycle.

FIG. 11 is a schematic cross-sectional view of the strip and the diesillustrating their relative positions soon after the cold-formingstrokes of the respective dies with a scrap illustration of the orbitalmotion of the female die and the relative position of the leading edgeof the female die at this stage of the cycle.

FIG. 12 is a schematic cross-sectional view of the strip and the diesillustrating their relative positions with the dies fully retracted witha scrap illustration of the orbital motion of the female die and therelative position of the leading edge of the female die at this stage ofthe cycle.

FIG. 13 is a schematic cross-sectional view of the strip and the diesillustrating their relative positions immediately prior to thecold-forming strokes of the respective dies with a scrap illustration ofthe orbital motion of the female die and the relative position of theleading edge of the female dies at this stage of the cycle.

FIG. 14 is a schematic cross-sectional view of preferred embodiment of abuilding element in accordance with a preferred embodiment of theinvention taken along the line 14—14 of FIG. 1.

FIG. 15 is a schematic perspective view of a building element inaccordance with a preferred embodiment of the invention.

FIG. 16 is a schematic enlarged cross-sectional view of importantcomponents of a pair of building elements formed in accordance with apreferred embodiment of the invention.

FIG. 17 is a schematic perspective view of a building made of elementsin accordance with a preferred embodiment of the invention.

FIG. 18 is a schematic perspective view of another building made ofelements in accordance with a preferred embodiment of the invention.

FIG. 19 is a schematic plan view of cold-forming apparatus in accordancewith a preferred embodiment of another aspect of the invention.

FIG. 20 is a schematic side elevation view of cold-forming apparatusillustrated in FIG. 19 along the line 20—20 of FIG. 19.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIG. 1 schematically illustrates a cold-forming machine in accordancewith one embodiment of one aspect of the invention.

The machine comprises a frame 1 having transverse generally parallel andcoextensive members 2, cross members 2′ and longitudinal generallyparallel and coextensive members 3 which are joined together to form a“box” configuration. The illustrated frame 1 has a height of 2 meters, awidth of 1.67 meters and a length of 3.5 meters. The present inventionthus facilitates cold-forming essentially flat strip into buildingelements of the requisite kind along a transit path that may extend lessthan 4 meters.

Towards the front of the machine, an uncoiler 4 is provided to support acoil 5 of metal strip 6. The coil 5 is rotatably mounted thereon toenable the strip 6 to be readily unwound. Typically the strip issuingfrom the coil has a thickness in the range of 0.8 to 1.2 millimeters anda width of about 1.245 meters.

The frame 1 is lifted about a transverse horizontal axis extending alonga bottom edge 7 by a lifting mechanism 8. The lifting mechanism 8comprises a hydraulic ram extending between the ground and the frame 1.

Alternatively the lifting mechanism may be a mechanical jack or otherlifting device.

Mounted within the frame 1 are a set of cold-forming die means, edgeforming means, guide means and strip drive means.

The strip drive means 9, as best seen and illustrated in FIGS. 1 and 2,comprises a pair of coextensive substantially parallel drive rollers 10,11 between which strip 6 is received from the coil 5 and issued in asubstantially flat configuration. The strip drive means also includes anelectric motor 12 and a chain or belt drive 13 to drive rollers 10, 11.A pair of pressing rolls 14 are provided to enhance traction between thedrive rollers and the strip 6. The strip drive means 9 is mounted to theframe 1 in advance of the guide means 15.

The guide means 15 is provided to pass the strip 6 to the cold-formingdie means 30.

The die means 30 provides an arcuate nip 40 to receive the strip 6.

The guide means 15 presents the strip to the arcuate nip 40 in a shapecorresponding generally to that arcuate shape in cross-section withoutplastically deforming the strip. That is to say, the strip 6 is passedto the nip 40 in an essentially channel shape without the strip 6 beingplastically deformed into that shape.

As illustrated in FIGS. 2, 3, 4 and 5, the guide means 15 comprises aplurality of guide members mounted to the frame 1 in the form of anumber of rotatable wheels 16 having elastomeric tire 17 disposed on oneside of the strip 6, rolls 18 having elastomeric surfaces disposed onthe other side of the strip 6, edge guides 19 to constrain lateralmovement of the strip 6 and permit the edges of the strip to slidetherethrough. Additional edge guides 20 disposed immediately in advanceof the cold-forming die means 30 may be provided to enhance guiding ofthe strip and to bend the edge margins inwardly without plasticdeformation thereof to enhance steering.

FIGS. 3, 4 and 5 best illustrate the progressive change in shape of thestrip 6 in transverse section from a flat sheet as it issues from thedrive rollers 10, 11 to a channel shape as presented to the cold-formingdie means 30 without plastic deformation as it passes the respectiveguides at locations indicated by lines 3—3, 4—4, and 5—5 respectively ofFIG. 2.

The cold-forming die means 30, as best seen in FIG. 6, mounted onintermediate transverse members 21 of the frame 1, comprise a set ofcoextensive generally in register dies between which the strip 6 isreceived. The set comprises a male die 22 having a concave leading edge24 and a female die 23 having a convex leading edge 25. The arcuate nip40 is formed by the leading edges 24, 25 of the dies 22, 23. The maledie 22 and female die 23 are driven towards one another to plasticallydeform the strip 6 into a channel section. The concave leading edge 24is provided with a coextensive protrusion 26 and the convex leading edge25 is provided with a coextensive recess 27. At the same time that thedies 22, 23 mate to plastically deform the strip 6 into channel section,the protrusion 26 and recess 27 of the respective dies 22, 23 mate toform a transverse rib 28 in the strip 6.

The dies 22, 23 are mounted on respective sets of crankshafts 38,39driven by means of a chain and sprocket arrangement. The dies 22, 23 aregeared to each other to maintain the protrusion 26 of the male die 22 inregister with the recess 27 of the female die 23 thereby portions of thestrip 6 are pushed into the recess 27 to permanently deform the strip 6to form a rib 28.

The strip 6 is passed into the nip 40 between the male and female dies22, 23. The dies 22, 23 are provided with cooperating orbital motionsthat bring the dies 22, 23 together to form a rib 28 in the strip 6 andto form the strip 6 into channel section. The dies 22, 23 engagerespective opposite sides of the strip 6 as it travels along a transitpath through the apparatus, plastically deform the engaged portions ofthe strip 6 to form a transverse rib 28 and advance with the sheet asdeformation occurs then releases the ribbed strip 6 as the strip 6advances on further along its transit path. At the same time, by virtueof their respective concave and convex edges 24, 25 the dies 22, 23plastically deform the sheet into a channel section. The step isrepeated with each sweep of the dies 22, 23 thereby forming amultiplicity of ribs 28. In the illustrated embodiment the ribs 28 arein the form of corrugations. The corrugations are substantiallysinusoidal in cross-section and extend transversely across a majorportion of the strip 6.

Each die 22, 23 maintains its orientation in relation to the other dieas it sweeps about its orbital path. FIGS. 10 to 13 illustrate in scrapside view the orbital path of the dies 22, 23.

As illustrated in FIG. 6, the crank mechanism comprises two sets of fourcrankshafts 38, 39 each set respectively rotatably supporting each die22, 23. Four bearing housings are mounted on each die 22, 23, with twohousings disposed on opposite edge margins of each die 22, 23. One pairof housings 31 is mounted towards the leading end of the dies 22, 23 andthe other pair of housings 32 towards the trailing end.

Each set of four crankshafts 38, 39 are rotatably supported by eightbearing housings 33 mounted on the frame 1, two housings 33 for eachcrankshaft, and driven by an electric motor 34, for example, a 7 kWthree phase motor, through a chain and sprocket arrangement 35 providinga gear reduction of, for example, five to one. As illustrated by FIGS. 1and 6, the four drive sprockets 36 which drive crankshafts of the maledie 22 rotate the crankshafts in a counterclockwise direction and byrunning the back of the chains against the drive sprockets 37 of thefemale die 23 these crankshafts are driven clockwise.

In the illustrated embodiment, the one electric motor 34 drives both thedrive chain adjacent one edge of dies 22, 23 and the drive chainadjacent the other edge thereby facilitating synchronisation of movementof the dies 22, 23.

The dies 22, 23 are geared to one another so that they move towards oneanother to engage the strip 6 received between them, advance with thestrip 6 along a transit path therebetween then disengage from the strip6 as they move further along their respective orbital path created bythe movement of the crankshafts. The offset of each crankshaft is, forexample, 6½ mm thereby providing each die 22,23 with 13 mm eccentricdisplacement per revolution.

FIG. 6 illustrates the dies 22, 23 in the retracted positioncorresponding to that illustrated in FIG. 13.

The dies 22, 23 are thus provided with both vertical and horizontalmovement as their cooperating respective concave and convex edges 24, 25sweep an orbital path (as illustrated in FIGS. 10 to 13 in scrap sideview) without departing from their orientation towards one another.

FIG. 10 schematically illustrates the two dies 22, 23 at a position ofengagement at an end of a cold-forming step and FIGS. 11 to 13illustrate their relative positions in three other positions during oneorbit of the dies 22, 23. The concave edge 24 and the convex edge 25 liein register during each orbit. The crankshaft offset may be said toprovide the dies 22, 23 with both rotational and reciprocating actionwhich permits continuity of strip feed.

FIGS. 6, 7, 8 and 9 illustrate a preferred embodiment of a male die 22and female die 23. The male die 22 as illustrated in FIG. 9 in schematiccross-section is formed of three plates 81, 82, 83 bolted togetherhaving a concave leading edge 24. The intermediate plate 82 sandwichedbetween the other two plates 81, 83, extends from the leading end of thedie 22, to form a protrusion 26, by a distance in the range of, forexample, 10 to 12 mm.

The female die 23 is formed of three plates bolted together having aconvex leading edge 25 with two outer plates 84, 85 extending beyond theother thicker plate 86 by a distance in the range of, for example, 10 to12 mm to provide a channelled leading edge 25.

Appropriate setting up and adjustment of the dies is significant inproducing quality elements.

Each die must be accurately set to properly define a nip between them ofappropriate radius of curvature.

The dies, once in place, have to be calibrated prior to operation sothat the radius of curvature of the leading end of one die substantiallycorresponds to that of the other.

However, it has been found beneficial to provide means for allowingadjustment of the radius of curvature of the leading edge of at leastone of the dies to fine tune the corrugating operation and enable theapparatus to accommodate fluctuations in strip thickness and other stripdefects and to accommodate fluctuations due to misalignment and wear ofcomponents of apparatus in the cold-forming line. Other problems thatmay arise include oil canning.

Adjustment of the radius of curvature of the leading edge of one of thedies, generally in the order of only a few millimeters, cansignificantly ameliorate such problems.

Adjustment means may also reduce the need to cease operation and removeand replace one of the dies with another of differing leading edgeradius of curvature.

In accordance with one preferred aspect of the invention there isprovided means for allowing the leading edge of the female die to changeits arcuate radius of curvature.

To this end, the female die 23 is formed in two identical half segments90, 91 which are held side to side to form the completed die 23 having aleading end and a tailing end.

FIGS. 6, 7, 8 and 9 illustrate the construction of the die segmentswhich are supported on the frame by means of bearings and cranks asdescribed previously. The half segments 90, 91 are provided with a gapof, for example, 2 mm to 3 mm between adjacent corners 93, 94 of theleading end of the die. The gap may be provided by bevelling, such as,for example, shaving off 1-1.5 mm from each adjacent corner 93, 94 ofthe half segments 90, 91.

The leading edge 25 of each half segment 90, 91 is of generally channelformation so that the die defines a channel 27 to receive the leadingedge protrusion 26 of the male die 22. 23.

The half segments 90,91 are hinged to one another at a position towardsthe leading end of the die 23 by a pivot pin 92 so that the gap can beprovided between the half segments at the leading edge of the die 23.The width of the gap can be preset and/or may be adjusted after startup. In this way the radius of curvature of the female die 23 can beadjusted to differ from that of the male die 22, generally by the orderof only a few millimeters to address operational problems that mayarise.

That is to say, adjacent leading portions of the segments are hinged oneto the other to permit adjacent corners 93, 94 of leading portions ofthe segments 90, 91 to be spaced apart a predetermined distance and tobe moved towards and away from one another to permit adjustment to saidspacing and thus the radius of curvature of the leading edge.

Additionally the present preferred embodiment enables discreteadjustment of one half segment alone thereby providing more precision inthe fine tuning of the apparatus than has previously been possible.

A primary purpose of providing means to vary the radius of curvature ofthe dies is to assist in fine tuning the cold-forming step and as suchmay be used to address oil canning problems which can arise duringoperation of the apparatus due to variations in strip thickness, et al.

Means to adjust the radius of curvature of the leading edge of a die isprovided, inter alia, to address the problem of excessive oil-canning atthe top of the channel and to enable the apparatus to provide asubstantially constant corrugation by means of either lessening orincreasing the depth of the corrugation towards the ends of thecorrugation. The adjustment means according to the preferred embodimentfacilitates elimination of any sign of oil-canning which may appear inthe portion of the channel at the ends of the corrugations which aredevoid of corrugations. If the channel is excessively corrugated thedies tends to pull said portion into compression and create problemsthere.

The adjustment means facilitates control of the apparatus in striking acompromise between excessive oil-canning and excessive corrugation.

Additionally, the present embodiment of the female die enablesadjustment of the position of either segment of the die to effectivelyenable the depth of the corrugation on one side of the element to bechanged without altering the other side.

As illustrated in FIG. 1, the ribbed strip 6 issues from the dies 22, 23and passes to edge forming means disposed immediately downstream of thedies means 30. The edge forming means is in the form of two pairs ofsets of coextensive edge forming rollers 41, 42 with each pair of setsof rollers 41, 42 operating on a respective longitudinal edge of thestrip 6 to form flanged edges 70, 71.

The strip 6 enters the sets of edge forming rollers 41, 42 where it isgripped along its edge margins. As it issues from the edge formers theformed element is directed upwardly, as illustrated by FIG. 1.

The apparatus is also provided with a set of shears (not shown) whichcuts the formed strip into building elements of predetermined length.The strip 6 issuing from the apparatus has a longitudinal radius ofcurvature R which forms an upwardly convex building element as bestillustrated by FIG. 15. The depth of the channel as best illustrated byFIG. 14 is in the order of 300 mm.

The requisite building element is formed in one pass through theapparatus and may be launched directly to its location in the buildingbeing erected.

FIG. 15 is a schematic perspective view of an element constructedaccording to a preferred embodiment of the invention and FIG. 16 is across-sectional view of a joint between two neighbouring elements havinga female edge flange 71 and a male edge flange 70. The male edge flangeformation 70 is of generally C-section having an inwardly opening mouth72 and having an out turned lip 73 folding back towards a distal outerface of the C-section and the female edge flange formation 71 is ofgenerally upwardly and outwardly extending L-section 74 having a downturned edge margin 75, said edge margin 75 being adapted in use to foldback towards the L-section 71. Edge flanges of the kind illustratedfacilitate jointing of adjacent elements edge to edge. Elements producedby the illustrated machine are typically 840-850 mm wide and 300 mm deepand as such are too heavy to be handled safely by manual labour.

In assembling the elements, it is advantageous to movably support eachelement as it is being located in position. Once the first element ispositioned subsequent elements are readily positioned side by side withneighbouring edge flanges 70, 71 overlapping. The overlapped flanges 70,71 may then be secured to one another by folding or bending the edgemargin of flange 71 under the edge margin of flange 70 as illustrated inphantom outline in FIG. 16. Alternatively the overlapping edge flangesmay be clinched or otherwise fastened to one another.

In another embodiment in accordance with another aspect of the inventionand as illustrated in FIG. 19 in plan view and FIG. 20 taken along theline 20—20 of FIG. 19, the frame 1 is supported on a cradle to turn theframe 1 about a longitudinal axis substantially parallel to the travelpath of the strip through the machine and hold it at a discreteorientation so that the element may issue at any desired discreteorientation. The longitudinal axis of the frame 1 may, for example, besupported to extend substantially horizontally and the frame 1 may beturned 90° from the orientation of the frame as illustrated in FIG. 1.The element C may thus issue from the trailing end of the frame 1 on itsedge and move towards one side of the frame 1 onto a runout table (notshown) rather than being launched into the air directly to its locationin the building being erected.

In accordance with a preferred embodiment, an array of elements issuingon their edge are joined (preferably by a splined overlap joint)sequentially end to end on the runout table to form a cylinder. Meansare provided to raise the cylinder to by a distance exceeding the heightof the cylinder on the runout table so that a subsequent array ofelements can be joined to one another to form another cylinder. Thecylinders are then jointed to one another edge to edge. The jointedcylinders are then raised by a distance exceeding the height of onecylinder so that the next cylinder can be assembled on the runout tableand subsequently jointed to the cylinder above. In this manner abuilding of the kind illustrated in FIG. 17 having a cylindricalperipheral wall can be assembled. Once sufficient cylinders are jointed,the jointed assembly may be lowered towards the ground so that thelowermost cylinder sits on its edge on a foundation. The roof may bepreformed or assembled on site and may be applied to the uppermostcylinder either prior to that cylinder being raised on the runout table,after the assembly has been placed on foundations or at any other stageof construction.

In another embodiment, the length of the element may be sufficient toenable its leading end to joined to its trailing end to form a cylinder.

In yet another embodiment, the array of elements on the runout table maybe sequentially joined end to end to form a constructional element ofsemi circular cross-section or the element may be cut to a length toform a constructional element of semi circular cross-section. Theseconstructional elements may be raised and jointed in a fashion similarto that described in relation to the cylinders except in this case thejointed assembly is hoisted into position to form a building of the kindillustrated in FIG. 18.

Important components of the machine of this embodiment, such as, forexample, the frame, the set of cold-forming die means, edge formingmeans, guide means and strip drive means are identical to thosedescribed with reference to FIGS. 1 to 18.

As illustrated in FIG. 19 the frame 1 is provided with a pair of steelrings 52, 53, each ring 52, 53 being welded to a respective end of theframe 58 by means of struts 51. Cradle means comprises a cradle 55, 56at each end of the frame 1 joined to one another by a pair of beams 58.Each cradle 55, 56 has two frame support rollers 57, 59 supporting eachof the two steel rings 52, 53 thereby enabling the frame 58 to sit inand discretely rotate on the cradle means. Each ring 52, 53 is turned insynchronisation with the other by a chain drive (not shown) in which aduplex chain wraps around three sprockets at each ring 52, 53 and aredriven at a controlled speed of turning.

In this embodiment the uncoiler is arranged to turn about a transverseaxis of the coil in synchronisation with the turning of the frame so asto continue to present the strip to the drive rollers 11 in the sameorientation.

Each of the four corners of the cradle means is provided with swing-outlegs 60. The legs 60 may be engaged by hydraulic jacks 61 to raise andlower the structure.

FIG. 20 illustrates a preferred orientation of the frame and andassociated orientation of the element C issuing from the machine.Illustrated in phantom outline are two other orientations of the frame1′, 1″ and the element C′, C″ wherein the frame has been turned about alongitudinal axis of the frame by 90 degrees and 180 degreesrespectively from that illustrated.

The structure may be raised and lowered to enable the machine to beloaded onto a vehicle tray. Additionally, it may be necessary to raiseand lower the structure to enable the frame 1 to be turned about itslongitudinal axis.

Particular embodiments of the invention have been described andillustrated by way of example, but it will be appreciated that othervariations of and modifications to the invention can take place withoutdeparting from the spirit and scope of the invention. For example, thebuilding elements may be used to construct a roof structure of abuilding or may be used to form the walls of a grain silo or likebuilding. Additionally the dies may be designed to enable two or morecorrugations to be formed simultaneously, that is to say, with eachorbit of the dies.

Further the radius of orbit of the dies of the preferred embodimentsillustrated is fixed. However, it would be possible to manufacture amachine with an adjustable radius on those cranks so as to provide anadjustable radius of orbit so as to provide the dies with a bigger pitchor a smaller pitch.

Additionally further, whereas orbital motion of the dies is preferred,the dies may, for example, be moved in simultaneously separatereciprocating motions in transverse planes to effect said plasticdeformation of the strip. For example the dies may be driven insimultaneous separate reciprocating horizontal and vertical motions.

What is claimed is:
 1. Apparatus for forming an elongate longitudinallyarcuate building element of channel cross-section having transverse ribsfrom sheet metal comprising a set of coextensive generally in registerdies through which a sheet of metal can be received, said set comprisinga male die and a female die which cooperate to form transverse ribs inthe sheet wherein further one of said male die and female die isprovided with a concave leading edge and the other die is provided witha convex leading edge thereby the dies cooperate to plastically deformthe sheet into a channel section, the dies being provided with orbitalmotions which cooperate to bring the dies into engagement with thesheet, draw the sheet along a transit path therebetween whilecold-forming the sheet and then disengage the sheet with each sweepabout their orbits.
 2. Apparatus according to claim 1 wherein the maledie is provided with an upright protrusion projecting from its leadingedge and extends along at least part of its length.
 3. Apparatusaccording to claim 1 wherein the female die is provided with acoextensive recess extending along at least part of its length. 4.Apparatus according to claim 2 wherein the protrusion extends a majorportion of its respective edge.
 5. Apparatus according to claim 3wherein the recess extends a major portion of its respective edge. 6.Apparatus according to claim 1 wherein the leading edges remain inregister during operation of the apparatus.
 7. Apparatus according toclaim 1 wherein the said set of dies are mounted on crank mechanisms toprovide the dies with said cooperating orbital motions.
 8. Apparatusaccording to claim 1 wherein the dies engage respective opposite sidesof the sheet as it travels along a transit path through the apparatus,plastically deform the engaged portions of the sheet to form transverseribs and advance with the sheet as deformation occurs, then release thesheet as it advances further along its transit path.
 9. Apparatusaccording to claim 1 wherein guide means are provided in advance of thedies to receive the strip from a coil in a substantially flatconfiguration and pass the strip to an arcuate nip formed by the leadingedges of the dies in a shape corresponding generally to that shape incross-section without plastically deforming the strip.
 10. Apparatusaccording to claim 1 wherein the apparatus further comprises edge flangeforming means to operate on each longitudinal edge of the sheet. 11.Apparatus according to claim 10 wherein the edge flange forming meanscomprise at least two pairs of cooperating edge forming rollers witheach pair of rollers operating on a respective longitudinal edge to formflanged edges.
 12. Apparatus according to claim 10 wherein the flangededges of each sheet is formed as respective male and female formationsso that two elements disposed side by side with overlapped flanged edgesenable the male formation of one element to nestle in the femaleformation of the other element.
 13. Apparatus according to claim 1wherein the sheets are provided from a coil of strip and that theapparatus further comprises shears to cut said strip into sheets ofpredetermined length.
 14. Apparatus according to claim 13 wherein theshears are provided downstream of the forming dies so that thecold-formed strip is cut into cold-formed elements.
 15. Apparatusaccording to claim 1 wherein the transverse ribs comprise corrugations.16. Apparatus according to claim 1 wherein the dies are so geared to oneanother that they move towards one another to engage the strip receivedbetween them, advance with the strip along a transit path therebetweenthen disengage from the strip as they move further along respectiveorbital path created by movement of crankshafts.
 17. Apparatus accordingto claim 16 wherein each crankshaft is offset to provide each die witheccentric displacement with respect to a frame thereby providing thedies with both rotational and reciprocating action which permitscontinuity of strip feed.
 18. Apparatus according to claim 16 whereinthe dies are provided with both vertical and horizontal movement astheir cooperating respective concave and convex edges sweep said orbitalpath without departing from their orientation towards one another. 19.Apparatus according to claim 1 wherein the apparatus further includes aframe having transverse generally parallel and coextensive members andlongitudinal generally parallel and coextensive members which are joinedtogether to form a “box” configuration.
 20. Apparatus according to claim19 wherein the frame is mounted to rotate about a longitudinal axis of atravel path of strip passing through the frame to enable the frame to beoriented at discrete orientations about said axis.
 21. Apparatusaccording to claim 19 wherein mounted within the frame are the set offorming dies, an edge forming means, a strip guide means and a stripdrive means.
 22. Apparatus according to claim 21 wherein the strip drivemeans comprises a pair of coextensive substantially parallel drive rollsbetween which strip is received from the coil and issued in asubstantially flat configuration, and is provided in advance of thedies.
 23. Apparatus according to claim 19 wherein guide means areprovided to pass the strip to an arcuate nip formed by the leading edgesof the dies in a shape corresponding generally to that shape incross-section without plastically deforming the strip.
 24. Apparatusaccording to claim 21 wherein said edge forming means is in the form oftwo pairs of coextensive edge forming rollers with each pair of rollersoperating on a respective longitudinal edge of the strip to form aflanged edge.
 25. Apparatus according to claim 19 wherein the set ofcold-forming dies are mounted on intermediate transverse members of theframe.
 26. Apparatus according to claim 1 wherein the dies are providedwith means to adjust the radius of curvature of either or both therespective concave leading edge or the convex leading edge. 27.Apparatus according to claim 26 wherein adjustment of the radius ofcurvature of a leading edge is effected by means of providing a femaledie formed of a plurality of segments held side to side having a gapprovided between at least a portion of each of the segments, the widthof the gap being adjustable so as to effect adjustment of the radius ofcurvature of the leading edge.
 28. Apparatus according to claim 1wherein any one of the male die and the female die is formed of twosubstantially identical half segments.
 29. Apparatus according to claim28 wherein the half segments are hinged to one another towards theirleading end.
 30. A process of forming an elongate longitudinally arcuatebuilding element of channel cross-section having transverse ribs fromsheet metal comprising the steps of; directing sheet material to a nipof a set of dies, providing a set of coextensive generally in registerdies having a nip through which a sheet of metal can be received, saidset comprising a male die and a female die which cooperate to formtransverse ribs in the sheet wherein further one of said male die andfemale die is provided with a concave leading edge and the other die isprovided with a convex leading edge thereby the dies cooperate toplastically deform the sheet into a channel section and driving saiddies to bring them together to form said transverse ribs in the sheetand to plastically deform the sheet into channel section prior todisengaging the cold-formed element, the dies being provided withorbital motions which cooperate to bring the dies into engagement withthe sheet, draw the sheet along a transit path therebetween whilecold-forming the sheet and then disengage the sheet with each sweepabout their orbits.
 31. A process according to claim 30 wherein theleading edges are held in register during operation of the apparatus.32. A process according to claim 30 wherein the said set of dies aremounted on crank mechanisms to provide the dies with said cooperatingorbital motions.
 33. A process according to claim 30 wherein the processfurther comprises the step of edge flange forming each longitudinal edgeof the sheet.
 34. A process according to claim 30 wherein the processincludes the step of providing metal sheets from a coil of strip andthen cutting said strip into sheets of predetermined length.